Question

Find an equation of the line passing through the given points (1,-3) and (3,3)

Answer 1

ANSWER: y= 3x - 6

STEP-BY-STEP EXPLANATION:

(1,-3) and (3,3)

X1=1           X2=3

Y1= - 3       Y2=3

1) Find the slope of the line.

To find the slope of the line passing through these two points we need to use the slope  formula:

m = $\frac{Y2-Y1}{X2-X1}$

m= $\frac{3-(-3)}{3-1}$   m=$\frac{6}{2}$ = 3

2)Use the slope to find the y-intercept.

Now that we know the slope of the line is 3 we can plug the slope into the equation and  we get:

y= 3x+b

Next choose one of the two point to plug in for the values of x and y. It does not matter  which one of the two points you choose because you should get the same answer in either  case. I generally just choose the first point listed so I don’t have to worry about which  one I should choose.

y= 3x+b       point (1,-3)

-3= 3(1) + b

-3-3=b

-6=b

3)Write the answer.

Using the slope of 3 and the y-intercept of -6 the answer is:

y = 3x - 6